<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <div id="box">123</div>
    <script>
      'use strict' // 开启严格模式
      let abc = 100
      console.log(abc)

      function test() {
        console.log('this:', this)
      }

      test()

      let obj = { name: '文理东', age: 88 }
      delete obj.age
      console.log(obj)
    </script>
  </body>
</html>
